摘要:

The total number of nucleated cells in the bone marrow of SAS/4 mice increase some twofold between 1 and 24 months of age but when related to body weight remains essentially constant over a wide range of ages. The concentration of CFU-S in femoral marrow is also constant with age and since other bones containing marrow appear, at least in young mice, to have the same CFU-S concentration as the femur it is concluded that the CFU-S compartment size of the whole bone marrow is independent of age when expressed on a body weight basis. In contrast, both the absolute number and the concentration of exogenous CFU-S in the spleen decline markedly in old mice. Similarly there is a decline in the number of endogenous colony-forming cells and the spleens of 24-month-old mice seem virtually devoid of such colonies. Not only were older mice less capable of supporting the growth of endogenous colonies, but their spleens also appear to provide a poorer environment for exogenous colony growth when compared with growth in younger recipient spleens.

ISSN:0304-324X    

DOI:10.1159/000212025

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

In an initial study, differences in learning and immediate recall were observed for groups of young and aged subjects on several measures. Retest data showed some differential loss for aged subjects after 1 week. Conclusions regarding long-term retention per se were not possible due to the nature of the design. In a second study, additional aged and young groups of subjects were run under delayed recall conditions. The data from these two groups were combined with data from the first study, with care taken to match subjects on a number of variables (health, education, intelligence). The results showed age-related differences for measures of learning and immediate recall but not for delayed 1 week retention.

ISSN:0304-324X    

DOI:10.1159/000212026

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Electroencephalographic (EEG) changes, as measured by the awake state, slow-wave sleep (SWS), rapid-eye movement (REM) patterns and ratio of REM/total sleep, were recordered in aging male mice of DBA/2J and C57BL/6J strains. Results indicate that there is a significant increase in the awake state accompanied by significant decrease in SWS with advancing age for both strains, although these changes appear more pronounced in DBA/2J mice than C57BL/6J mice. Of considerable significance is the finding that REM sleep is absent in mice of DBA/2J strain at 23.5 months of age. Based on these findings, the conclusion was reached that strain DBA/2J ages significantly faster than C57BL/6J. The difference in aging between the two strains emphasizes the need for additional studies dealing with genetic aspects of aging.

ISSN:0304-324X    

DOI:10.1159/000212027

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Senile muscles of the rat (28–36 months) show loss of overall activity of glycolytic and aerobic enzymes. However, there is a differential loss and shift of enzyme activity pattern in the three types of muscles. The extensor digitorum longus (EDL) and diaphragm show a decrease of ratios of glycolytic to aerobic-oxidative enzymes. This shift to a more oxidative type of metabolism is not observed in the soleus muscle. Decrease of enzyme activities is least marked in the diaphragm muscle. Biochemical analysis shows a trend to levelling out of metabolic differences between the different muscle types. This trend of ‘dedifferentiation’ is most marked when comparing EDL and soleus, least marked when comparing EDL and diaphragm muscle. The histochemical analysis shows a shift from the original mixed to a more uniform pattern of muscle fibres in the EDL and soleus muscle; this levelling-out of differences between enzymatic activities of different muscle fibres is not observed in the diaphragm muscle. Preferential atrophy and loss of ATPase activity in type II muscle fibres in the soleus muscle and the occurrence of ‘type grouping’ are further characteristic features of senile muscle change. The findings show general (i.e. loss of enzyme activities) and differential trends of biochemical and histochemical enzyme changes in different types o

ISSN:0304-324X    

DOI:10.1159/000212028

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Two inbred strains of mice, C57BL/6J and DBA/2J, ranging in age from 2 to 38 months, were tested in an open field using the free exploration method. Scores were obtained for locomotor activity, exploratory behavior and emotionality. Strain differences were observed for all three variables. Beginning at late maturity (12 months), locomotor activity decreased with increasing age. Exploratory behavior was at a low level for DBA/2J mice at all ages. For C57BL/6J mice, exploratory behavior decreased significantly between 2 and 6 months and remained stable thereafter. Emotionality remained unchanged with advancing age for both strains of mice.

ISSN:0304-324X    

DOI:10.1159/000212029

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212030

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The Orgel hypothesis receives considerable attention as a possible explanation for the phenomenon of senescence. Experimental observations which argue in favor of the Orgel hypothesis are discussed, and criticized in part. This is followed by a presentation of experimental data which argue in opposition to the notion. On the basis of the considerable body of data which argue in opposition to the Orgel theory, a call for reappraisal of the applicability of this theory to the phenomenon of senescence is suggested.

ISSN:0304-324X    

DOI:10.1159/000212031

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

A major prediction of Orgel’s theory is that the misincorporation of amino acids into proteins will increase with age. This has not yet been tested experimentally. Indirect methods have been used to search for the presence of altered proteins in ageing cells or organisms, but these would not necessarily detect a low level of mistakes, nor do they distinguish between errors in synthesis and post-synthetic changes. Nevertheless, some experimental results have been obtained from genetic and biochemical studies with fungi and fibroblasts which confirm certain predictions of the protein error theor

ISSN:0304-324X    

DOI:10.1159/000212032

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212033

出版商:S. Karger AG    

年代:1975

数据来源: Karger